Weak DH primes and openssh

Darren Tucker dtucker at zip.com.au
Thu May 28 10:14:07 AEST 2015


On Sun, May 24, 2015 at 9:20 AM, Darren Tucker <dtucker at zip.com.au> wrote:

> [...]
> The other possible action that IMO would be reasonable but is not listed:
> remove all of the 1kbit and 1.5kbit groups
>

After some consideration we have decided to remove[1] the 1k bit groups
from the moduli file.   Vendors may want to consider doing this even for
older versions of OpenSSH (either by importing the new file, or by removing
them from the existing file) as it will result in stronger groups being
used for diffie-hellman-group-exchange-sha{1,256} transparently even if the
client prefers 1k bit groups (eg PuTTY and derivatives when using 128bit
ciphers).

[1]
https://anongit.mindrot.org/openssh.git/commit/?id=5ab7d5fa03ad55bc438fab45dfb3aeb30a3c237a

-- 
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.


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